Change SourceInjector API to accept a generic ThreeMLModelFoldingInterface

[israelmcmc]

Currently, SourceInjector accepts all the inputs to initialize a FullDetectorResponse:

cosipy/cosipy/source_injector/source_injector.py

Lines 19 to 32 in 266e133

	Parameters
	----------
	response : str or pathlib.Path
	The path to the response file
	response_frame : str, optional
	The frame of the Compton data space (CDS) of the
	response. It only accepts `spacecraftframe` or
	"galactic". (the default is `spacecraftframe`, which means
	the CDS is in the detector frame.)
	pa_convention : str, optional
	Polarization angle convention for polarization-enabled
	detector-frame responses. Must be one of ('RelativeX',
	'RelativeY', 'RelativeZ') when the response includes a
	`Pol` axis and `response_frame="spacecraftframe"`.

At first order, SourceInjector should accept a FullDetectorResponse object instead, to avoid opening multiple time.

However, now that we have the interfaces refactoring, we can go further and accept a generic ThreeMLModelFoldingInterface, and use it to convolve a generic model:

cosipy/cosipy/interfaces/source_response_interface.py

Lines 16 to 35 in ae814f6

	@runtime_checkable
	class ThreeMLModelFoldingInterface(Protocol):
	def set_model(self, model: Model):
	"""
	The model is passed as a reference and it's parameters
	can change. Remember to check if it changed since the
	last time the user called expectation.
	"""
	@runtime_checkable
	class UnbinnedThreeMLModelFoldingInterface(ThreeMLModelFoldingInterface, ExpectationDensityInterface, Protocol):
	"""
	No new methods. Just the inherited ones.
	"""
	@runtime_checkable
	class BinnedThreeMLModelFoldingInterface(ThreeMLModelFoldingInterface, BinnedExpectationInterface, Protocol):
	"""
	No new methods. Just the inherited ones.
	"""

Out current standard implementation of this interface is BinnedThreeMLPointSourceResponse. You can see an usage example in the Crab fit tutorial.

This is also related to #499: if the user passes a UnbinnedThreeMLModelFoldingInterface, we can inject event data right from the same class.